﻿using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;

namespace FtpClient
{
    public class FtpHelper
    {
        #region 属性与构造函数

        /// <summary>
        /// IP地址
        /// </summary>
        public string RemoteHost { get; set; }

        /// <summary>
        /// 相对路径
        /// </summary>
        public string RelatePath { get; set; }

        /// <summary>
        /// 端口号
        /// </summary>
        public int RemotePort { get; set; }

        /// <summary>
        /// 用户名
        /// </summary>
        public string RemoteUser { get; set; }

        /// <summary>
        /// 密码
        /// </summary>
        public string RemotePass { get; set; }

        /// <summary>
        /// 当前服务器目录
        /// </summary>
        public string RemotePath { get; set; }

        public FtpHelper()
        {

        }

        public FtpHelper(string ipAddr, int port, string userName, string password)
        {
            this.RemoteHost = ipAddr;
            this.RemotePort = port;
            this.RemoteUser = userName;
            this.RemotePass = password;
        }

        #endregion

        #region 方法

        public event EventHandler ProgressChange;

        /// <summary>
        /// 下载文件
        /// </summary>
        /// <param name="filePath"></param>
        /// <param name="isOk"></param>
        public void DownLoad(string filePath, out bool isOk)
        {
            string fileName = Path.GetFileName(RemotePath);

            if (File.Exists(filePath))
            {
                long remotingSize = GetFileSize(fileName);

                FileInfo fileinfo = new FileInfo(filePath);
                long localSize = fileinfo.Length;

                if (remotingSize != localSize)//断点续传
                {
                    GetBrokenFile(RemotePath, filePath, localSize);
                }
            }
            else
            {
                GetFile(fileName, filePath);//下载文件
                System.Windows.Forms.MessageBox.Show("文件" + filePath + "已经下载");
            }
            isOk = true;
            //string method = WebRequestMethods.Ftp.DownloadFile;
            //var statusCode = FtpStatusCode.DataAlreadyOpen;
            //FtpWebResponse response = callFtp(method);
            //ReadByBytes(filePath, response, statusCode, out isOk);
        }

        public void UpLoad(string file, out bool isOk)
        {
            Put(file);
            isOk = true;
           
        }

        /// <summary>
        /// 删除文件
        /// </summary>
        /// <param name="isOk"></param>
        /// <returns></returns>
        public string[] DeleteFile(out bool isOk,string name)
        {
            string method = WebRequestMethods.Ftp.DeleteFile;
            var statusCode = FtpStatusCode.FileActionOK;
            FtpWebResponse response = callFtp(method,name);
            return ReadByLine(response, statusCode, out isOk);
        }

        /// <summary>
        /// 展示目录
        /// </summary>
        public string[] GetStrFileList(out bool isOk)
        {
            //建立连接
            if (!bConnected)
            {
                Connect();
            }

            //建立进行数据连接的socket
            Socket socketData = CreateDataSocket();

            //传送命令
            SendCommand("LIST " + RemotePath);

            //分析应答代码
            if (!(iReplyCode == 150 || iReplyCode == 125 || iReplyCode == 226))
            {
                throw new IOException(strReply.Substring(4));
            }

            //获得结果
            strMsg = "";
            while (true)
            {
                int iBytes = socketData.Receive(buffer, buffer.Length, 0);
                strMsg += Encoding.UTF8.GetString(buffer, 0, iBytes);
                if (iBytes < buffer.Length)
                {
                    break;
                }
            }
            char[] seperator = { '\n' };
            string[] strFileList = strMsg.Split(seperator);
            socketData.Close();//数据socket关闭时也会有返回码
            if (iReplyCode != 226)
            {
                ReadReply();
                if (iReplyCode != 226)
                {
                    throw new IOException(strReply.Substring(4));
                }
            }
            isOk = true;
            return strFileList;
        }

        /// <summary>
        /// 设置上级目录
        /// </summary>
        public void SetPrePath()
        {
            string relatePath = this.RemotePath;
            if (string.IsNullOrEmpty(relatePath) || relatePath.LastIndexOf(@"\") == 0|| relatePath.LastIndexOf("/") == 0)
            {
                SendCommand("PWD ");
                if(iReplyCode==257)
                {
                    relatePath = strReply.Substring(5, strReply.LastIndexOf("'") - 5);
                }
            }
            else
            {
                relatePath = relatePath.Substring(0, relatePath.LastIndexOf(@"\"));
            }
            ChDir(relatePath.Trim());
        }

        #endregion

        #region 登陆字段、属性
        /// <summary>
        /// 是否登录
        /// </summary>
        private Boolean bConnected;

        public Boolean Connected
        {
            get { return bConnected; }
            set { bConnected = value; }
        }
        #endregion

        #region 连接
        /// <summary>
        /// 建立连接
        /// </summary>
        public void Connect()
        {
            socketControl = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            IPEndPoint ep = new IPEndPoint(IPAddress.Parse(RemoteHost), RemotePort);
            //连接
            try
            {
                socketControl.Connect(ep);
            }
            catch (Exception)
            {

                throw new IOException("Could not connect to remote server");
            }

            //获取应答码
            ReadReply();
            if (iReplyCode != 220)
            {
                DisConnect();
                throw new IOException(strReply.Substring(4));
            }

            //登陆
            SendCommand("USER " + RemoteUser);
            if (!(iReplyCode == 331 || iReplyCode == 230))
            {
                CloseSocketConnect();//关闭连接
                throw new IOException(strReply.Substring(4));
            }
            if (iReplyCode != 230)
            {
                SendCommand("PASS " + RemotePass);
                if (!(iReplyCode == 230 || iReplyCode == 202))
                {
                    CloseSocketConnect();//关闭连接
                    throw new IOException(strReply.Substring(4));
                }
            }
            bConnected = true;
            SetPrePath();
            //切换到初始目录
            if (!string.IsNullOrEmpty(RemotePath))
            {
                ChDir(RemotePath);
            }
        }

        /// <summary>
        /// 关闭连接
        /// </summary>
        public void DisConnect()
        {
            if (socketControl != null)
            {
                SendCommand("QUIT ");
            }
            CloseSocketConnect();
        }
        #endregion

        #region 传输模式
        /// <summary>
        /// 传输模式：二进制类型，ASCII类型
        /// </summary>
        public enum TransferType
        {
            Binary,
            ASCII
        }

        /// <summary>
        /// 设置传输模式
        /// </summary>
        /// <param name="ttType">传输模式</param>
        public void SetTransferType(TransferType ttType)
        {
            if (ttType == TransferType.Binary)
            {
                SendCommand("TYPE I");//binary类型传输
            }
            else
            {
                SendCommand("TYPE A");//ASCII类型传输
            }
            if (iReplyCode != 220&&iReplyCode!=330)
            {
                throw new IOException(strReply.Substring(4));
            }
            else
            {
                trType = ttType;
            }
        }

        /// <summary>
        /// 获得传输模式
        /// </summary>
        /// <returns>传输模式</returns>
        public TransferType GetTransferType()
        {
            return trType;
        }
        #endregion

        #region 私有方法

        /// <summary>
        /// 调用Ftp,将命令发往Ftp并返回信息
        /// </summary>
        /// <param name="method">要发往Ftp的命令</param>
        /// <returns></returns>
        private FtpWebResponse callFtp(string method,string name)
        {
            string uri = string.Format("ftp://{0}:{1}{2}", this.RemoteHost, this.RemotePort, this.RelatePath);
            Console.WriteLine(uri);
            FtpWebRequest request; request = (FtpWebRequest)FtpWebRequest.Create(uri+"/"+name);
            request.UseBinary = true;
            request.UsePassive = true;
            request.Credentials = new NetworkCredential(RemoteUser, RemotePass);
            request.KeepAlive = false;
            request.Method = method;
            FtpWebResponse response = (FtpWebResponse)request.GetResponse();
            return response;
        }

        /// <summary>
        /// 按行读取
        /// </summary>
        /// <param name="response"></pa
        /// ram>
        /// <param name="statusCode"></param>
        /// <param name="isOk"></param>
        /// <returns></returns>
        private string[] ReadByLine(FtpWebResponse response, FtpStatusCode statusCode, out bool isOk)
        {
            List<string> lstAccpet = new List<string>();
            int i = 0;
            while (true)
            {
                if (response.StatusCode == statusCode)
                {
                    using (StreamReader sr = new StreamReader(response.GetResponseStream()))
                    {
                        string line = sr.ReadLine();
                        while (!string.IsNullOrEmpty(line))
                        {
                            lstAccpet.Add(line);
                            line = sr.ReadLine();
                        }
                    }
                    isOk = true;
                    break;
                }
                i++;
                if (i > 10)
                {
                    isOk = false;
                    break;
                }
                Thread.Sleep(200);
            }
            response.Close();
            return lstAccpet.ToArray();
        }

        private void ReadByBytes(string filePath, FtpWebResponse response, FtpStatusCode statusCode, out bool isOk)
        {
            isOk = false;
            int i = 0;
            while (true)

            {
                if (response.StatusCode == statusCode)
                {
                    long length = response.ContentLength;
                    int bufferSize = 2048;
                    int readCount;
                    byte[] buffer = new byte[bufferSize];
                    using (FileStream outputStream = new FileStream(filePath, FileMode.Create))
                    {

                        using (Stream ftpStream = response.GetResponseStream())
                        {
                            readCount = ftpStream.Read(buffer, 0, bufferSize);
                            while (readCount > 0)
                            {
                                outputStream.Write(buffer, 0, readCount);
                                readCount = ftpStream.Read(buffer, 0, bufferSize);
                            }
                        }
                    }
                    break;
                }
                i++;
                if (i > 10)
                {
                    isOk = false;
                    break;
                }
                Thread.Sleep(200);
            }
            response.Close();
        }
        #endregion

        #region 文件操作

        /// <summary>
        /// 获得文件列表
        /// </summary>
        /// <param name="strMask">文件名的匹配字符串</param>
        /// <returns></returns>
        public string[] Dir(string strMask)
        {
            //建立连接
            if (!bConnected)
            {
                Connect();
            }

            //建立进行数据连接的socket
            Socket socketData = CreateDataSocket();

            //传送命令
            SendCommand("LIST " + strMask);

            //分析应答代码
            if (!(iReplyCode == 150 || iReplyCode == 125 || iReplyCode == 226))
            {
                throw new IOException(strReply.Substring(4));
            }

            //获得结果
            strMsg = "";
            while (true)
            {
                int iBytes = socketData.Receive(buffer, buffer.Length, 0);
                strMsg += GB2312.GetString(buffer, 0, iBytes);
                if (iBytes < buffer.Length)
                {
                    break;
                }
            }
            char[] seperator = { '\n' };
            string[] strFileList = strMsg.Split(seperator);
            socketData.Close();//数据socket关闭时也会有返回码
            if (iReplyCode != 226)
            {
                ReadReply();
                if (iReplyCode != 226)
                {
                    throw new IOException(strReply.Substring(4));
                }
            }
            return strFileList;
        }

        /// <summary>
        /// 获取文件大小
        /// </summary>
        /// <param name="strFileName">文件名</param>
        /// <returns>文件大小</returns>
        public long GetFileSize(string strFileName)
        {
            if (!bConnected)
            {
                Connect();
            }
            SendCommand("SIZE " + Path.GetFileName(strFileName));
            long iSize = 0;
            if (iReplyCode == 213)
            {
                iSize = Int64.Parse(strReply.Substring(4));
            }
            else
            {
                Console.WriteLine(strReply.Substring(4));
                //throw new IOException(strReply.Substring(4));
                //throw new IOException(strReply.Substring(4));
            }
            return iSize;
        }

        /// <summary>
        /// 删除
        /// </summary>
        /// <param name="strFileName">待删除文件名</param>
        public void Delete(string strFileName)
        {
            if (!bConnected)
            {
                Connect();
            }
            SendCommand("DELE " + strFileName);
            if (iReplyCode != 250)
            {
                throw new IOException(strReply.Substring(4));
            }
        }

        /// <summary>
        /// 重命名（如果新文件名与已有文件重名，将覆盖已有文件）
        /// </summary>
        /// <param name="strOldFileName">就文件名</param>
        /// <param name="strNewFileName">新文件名</param>
        public void Rename(string strOldFileName, string strNewFileName)
        {
            if (!Connected)
            {
                Connect();
            }
            SendCommand("RNFR" + strOldFileName);
            if (iReplyCode != 350)
            {
                throw new IOException(strReply.Substring(4));
            }
            //如果新文件名与原有文件名重名，将覆盖原有文件
            SendCommand("RNTO" + strNewFileName);
            if (iReplyCode != 250)
            {
                throw new IOException(strReply.Substring(4));
            }
        }

        #endregion

        #region 上传和下载

        /// <summary>
        /// 下载一批文件
        /// </summary>
        /// <param name="strFileNameMask">文件名的匹配字符串</param>
        /// <param name="strFolder">本地目录（）</param>
        public void Get(string strFileNameMask, string strFolder)
        {
            if (!bConnected)
            {
                Connect();
            }

            string[] strFiles = Dir(strFileNameMask);
            foreach (string strFile in strFiles)
            {
                if (!strFile.Equals(""))//一般来说strFiles的最后一个元素可能是空字符串
                {
                    if (strFile.LastIndexOf(".") > 1)
                    {
                        Get(strFile.Replace("\r", ""), strFolder, strFile.Replace("\r", ""));
                    }
                }
            }
        }

        /// <summary>
        /// 下载目录
        /// </summary>
        /// <param name="strRemoteFileName">要下载的文件名</param>
        /// <param name="strFolder">本地目录（不得以\结束）</param>
        /// <param name="strLocalFileName">保存在本地时的文件名</param>
        public void Get(string strRemoteFileName, string strFolder, string strLocalFileName)
        {
            if (strLocalFileName.StartsWith("-r"))
            {
                string[] infos = strLocalFileName.Split(' ');
                strRemoteFileName = strLocalFileName = infos[infos.Length - 1];

                if (!bConnected)
                {
                    Connect();
                }
                SetTransferType(TransferType.Binary);
                if (strLocalFileName.Equals(""))
                {
                    strLocalFileName = strRemoteFileName;
                }
                if (!File.Exists(strLocalFileName))
                {
                    Stream st = File.Create(strLocalFileName);
                    st.Close();
                }

                FileStream output = new FileStream(strFolder + "\\" + strLocalFileName, FileMode.Create);
                Socket socketData = CreateDataSocket();
                SendCommand("RETR" + strRemoteFileName);
                if (!(iReplyCode == 150 || iReplyCode == 125 || iReplyCode == 226 || iReplyCode == 250))
                {
                    throw new IOException(strReply.Substring(4));
                }
                while (true)
                {
                    int iBytes = socketData.Receive(buffer, buffer.Length, 0);
                    output.Write(buffer, 0, iBytes);
                    if (iBytes <= 0)
                    {
                        break;
                    }
                }
                output.Close();
                if (socketData.Connected)
                {
                    socketData.Close();
                }
                if (!(iReplyCode == 226 || iReplyCode == 250))
                {
                    ReadReply();
                    if (!(iReplyCode == 226 || iReplyCode == 250))
                    {
                        throw new IOException(strReply.Substring(4));
                    }
                }
            }
        }

        /// <summary>
        /// 下载一个文件
        /// </summary>
        /// <param name="strRemoteFileName">要下载的文件名</param>
        /// <param name="strFolder">本地目录（不得以\结束）</param>
        /// <param name="strLocalFileName">保存在本地时的文件名</param>
        public void GetFile(string strRemoteFileName, string filePath)
        {
            if (!bConnected)
            {
                Connect();
            }

            long fileSize = GetFileSize(strRemoteFileName);

            SetTransferType(TransferType.Binary);
            if (filePath.Equals(""))
            {
                filePath = strRemoteFileName;
            }
            if (!File.Exists(filePath))
            {
                Stream st = File.Create(filePath);
                st.Close();
            }

            FileStream output = new FileStream(filePath, FileMode.Create);
            Socket socketData = CreateDataSocket();
            SendCommand("RETR " + strRemoteFileName);
            if (!(iReplyCode == 150 || iReplyCode == 125 || iReplyCode == 226 || iReplyCode == 250))
            {
                Console.WriteLine(strReply.Substring(4));
                //throw new IOException(strReply.Substring(4));
            }
            while (true)
            {
                int iBytes = socketData.Receive(buffer, buffer.Length, 0);
                // 显示下载进度
                ProgressChange(1.0 * output.Position / fileSize, new EventArgs());

                output.Write(buffer, 0, iBytes);

                if (iBytes <= 0)
                {
                    break;
                }
            }
            output.Close();
            if (!socketData.Connected)
            {
                socketData.Close();
            }
            if (!(iReplyCode == 226 || iReplyCode == 250))
            {
                ReadReply();
                if (!(iReplyCode == 226 || iReplyCode == 250))
                {
                    throw new IOException(strReply.Substring(4));
                }
            }
        }

        /// <summary>
        /// 下载一个文件
        /// </summary>
        /// <param name="strRemoteFileName">要下载的文件名</param>
        /// <param name="filePath">本地保存目录和文件名</param>
        /// <param name="size"></param>
        public void GetBrokenFile(string strRemoteFileName, string filePath, long size)
        {
            if (!bConnected)
            {
                Connect();
            }
            SetTransferType(TransferType.Binary);
            FileStream output = new FileStream(filePath, FileMode.Append);
            Socket socketData = CreateDataSocket();
            SendCommand("REST " + size.ToString());
            SendCommand("RETR " + strRemoteFileName);
            if (!(iReplyCode == 150 || iReplyCode == 125 || iReplyCode == 226 || iReplyCode == 250))
            {
                throw new IOException(strReply.Substring(4));
            }
            while (true)
            {
                int iBytes = socketData.Receive(buffer, buffer.Length, 0);

                output.Write(buffer, 0, iBytes);
                if (iBytes <= 0)
                {
                    break;
                }
            }
            output.Close();
            if (socketData.Connected)
            {
                socketData.Close();
            }
            if (!(iReplyCode == 226 || iReplyCode == 250))
            {
                ReadReply();
                if (!(iReplyCode == 226 || iReplyCode == 250))
                {
                    throw new IOException(strReply.Substring(4));
                }
            }
        }

        /// <summary>
        /// 上传一批文件
        /// </summary>
        /// <param name="strFolder">本地目录（不得以\结束）</param>
        /// <param name="strFileNameMask">文件名匹配字符（可以包含*和？）</param>
        public void Put(string strFolder, string strFileNameMask)
        {
            string[] strFiles = Directory.GetFiles(strFolder, strFileNameMask);
            foreach (string strFile in strFiles)
            {
                //strFile是完整的文件名（包含路径）
                Put(strFile);
            }
        }

        /// <summary>
        /// 上传一个文件
        /// </summary>
        /// <param name="strFileName">本地文件名</param>
        public void Put(string strFileName)
        {
            if (!bConnected)
            {
                Connect();
            }
            Socket socketData = CreateDataSocket();
            SendCommand("STOR " + Path.GetFileName(strFileName));
            if (!(iReplyCode == 125 || iReplyCode == 150))
            {
                throw new IOException(strReply.Substring(4));
            }
            FileStream input = new FileStream(strFileName, FileMode.Open);
            int iBytes = 0;
            while ((iBytes = input.Read(buffer, 0, buffer.Length)) > 0)
            {
                socketData.Send(buffer, iBytes, 0);
            }
            input.Close();
            if (socketData.Connected)
            {
                socketData.Close();
            }
            if (!(iReplyCode == 226 || iReplyCode == 250))
            {
                ReadReply();
                if (!(iReplyCode == 226 || iReplyCode == 250))
                {
                    throw new IOException(strReply.Substring(4));
                }
            }
        }

        #endregion

        #region 目录操作

        /// <summary>
        /// 创建目录
        /// </summary>
        /// <param name="strDirName">目录名</param>
        public void MkDir(string strDirName)
        {
            if (!bConnected)
            {
                Connect();
            }
            SendCommand("MKD " + strDirName);
            if (iReplyCode != 257)
            {
                throw new IOException(strReply.Substring(4));
            }
        }

        /// <summary>
        /// 删除目录
        /// </summary>
        /// <param name="strDirName">目录名</param>
        public void RmDir(string strDirName)
        {
            if (!bConnected)
            {
                Connect();
            }
            SendCommand("RMD " + strDirName);
            if (iReplyCode != 250)
            {
                throw new IOException(strReply.Substring(4));
            }
        }

        /// <summary>
        /// 改变目录
        /// </summary>
        /// <param name="strDirName">新的工作目录名</param>
        public void ChDir(string strDirName)
        {
            if (strDirName.Equals(".") || strDirName.Equals(""))
            {
                return;
            }
            if (!bConnected)
            {
                Connect();
            }
            SendCommand("CWD " + strDirName);
            if (iReplyCode != 250)
            {
                throw new IOException(strReply.Substring(4));
            }
            this.RemotePath = strDirName;
        }

        #endregion

        #region 内部变量
        /// <summary>
        /// 服务器返回的应答信息（包含应答码）
        /// </summary>
        private string strMsg;
        /// <summary>
        /// 服务器返回的应答信息（包含应答码）
        /// </summary>
        private string strReply;
        /// <summary>
        /// 服务器返回的应答码
        /// </summary>
        private int iReplyCode;
        /// <summary>
        /// 进行控制连接的socket
        /// </summary>
        private Socket socketControl;
        /// <summary>
        /// 传输模式
        /// </summary>
        private TransferType trType;
        /// <summary>
        /// 接收和发送数据的缓冲区
        /// </summary>
        private static int BLOC_KSIZE = 512;
        private Byte[] buffer = new Byte[BLOC_KSIZE];

        /// <summary>
        /// 编码方式（为防止出现中文乱码采用GB2312编码方式）
        /// </summary>
        private Encoding GB2312 = Encoding.GetEncoding("utf-8");//Encoding.GetEncoding("gb2312");
        #endregion

        #region 内部函数

        /// <summary>
        /// 将一行应答字符串记录在strReply和strMsg
        /// 应答码记录在iReplyCode
        /// </summary>
        private void ReadReply()
        {
            strMsg = "";
            strReply = ReadLine();
            iReplyCode = Int32.Parse(strReply.Substring(0, 3));
        }

        /// <summary>
        /// 建立进行数据连接的socket
        /// </summary>
        /// <returns>数据连接socket</returns>
        private Socket CreateDataSocket()
        {
            SendCommand("PASV");
            if (iReplyCode != 227)
            {
                throw new IOException(strReply.Substring(4));
            }
            int index1 = strReply.IndexOf('(');
            int index2 = strReply.IndexOf(')');
            string ipData = strReply.Substring(index1 + 1, index2 - index1 - 1);
            int[] parts = new int[6];
            int len = ipData.Length;
            int partCount = 0;
            string buf = "";
            for (int i = 0; i < len && partCount <= 6; i++)
            {
                char ch = Char.Parse(ipData.Substring(i, 1));
                if (Char.IsDigit(ch))
                {
                    buf += ch;
                }
                else if (ch != ',')
                {
                    throw new IOException("Malformed PASV strReply:" + strReply);
                }
                if (ch == ',' || i + 1 == len)
                {
                    try
                    {
                        parts[partCount++] = Int32.Parse(buf);
                        buf = "";
                    }
                    catch (Exception)
                    {
                        throw new IOException("Malformed PASV strReply:" + strReply);
                    }
                }
            }
            string ipAddress = parts[0] + "." + parts[1] + "." + parts[2] + "." + parts[3];
            int port = (parts[4] << 8) + parts[5];
            Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            IPEndPoint ep = new IPEndPoint(IPAddress.Parse(ipAddress), port);
            try
            {
                s.Connect(ep);
            }
            catch (Exception)
            {
                throw new IOException("Can't connect to remote server");
            }
            return s;
        }

        /// <summary>
        /// 关闭socket连接（用于登录以前）
        /// </summary>
        private void CloseSocketConnect()
        {
            if (socketControl != null)
            {
                socketControl.Close();
                socketControl = null;
            }
            bConnected = false;
        }

        /// <summary>
        /// 读取Socket返回的所有字符串
        /// </summary>
        /// <returns>包含应答码的字符串行</returns>
        private string ReadLine()
        {
            while (true)
            {
                int iBytes = socketControl.Receive(buffer, buffer.Length, 0);
                strMsg += GB2312.GetString(buffer, 0, iBytes);
                if (iBytes < buffer.Length)
                {
                    break;
                }
            }
            char[] seperator = { '\n' };
            string[] mess = strMsg.Split(seperator);
            if (strMsg.Length > 2)
            {
                strMsg = mess[mess.Length - 2];
                //seperator[0]是10，换行符是由13和0组成的，分隔后10后面虽没有字符串，
                //但也会分配为空字符串给后面（也是最后一个）字符串数组，
                //所以最后一个mess是没用的空字符串，
                //但为什么不直接取mess[0]，因为只有最后一行字符串应答码与信息之间有空格
            }
            else
            {
                strMsg = mess[0];
            }
            if (!strMsg.Substring(3, 1).Equals(" "))
            //返回字符串正确的是以应答码（如220开头，后面接一空格，再接问候字符串）
            {
                return ReadLine();
            }
            return strMsg;
        }

        /// <summary>
        /// 发送命令并获取应答码和最后一行应答字符串
        /// </summary>
        /// <param name="strCommand">命令</param>
        private void SendCommand(String strCommand)
        {
            byte[] cmdBytes = GB2312.GetBytes((strCommand + "\r\n").ToCharArray());
            socketControl.Send(cmdBytes, cmdBytes.Length, 0);
            ReadReply();
        }

        #endregion
    }

    /// <summary>
    /// Ftp内容类型枚举
    /// </summary>
    public enum FtpContentType
    {
        undefined = 0,
        file = 1,
        folder = 2
    }
}
